Biphasic dermatofibrosarcoma protuberans with a labyrinthine plexiform high-grade fibrosarcomatous transformation

Successful Double DIEP Syngeneic Transplantation across Monozygotic Twins for Total Back Reconstruction

BACKGROUND

A 56-year-old woman presented with an extensive sarcoma requiring nearly total back resection. She had limited donor sites for reconstruction because of a previous laparotomy, but presented with a significantly larger, identical twin. Cancer has traditionally been considered a contraindication for vascularized composite allotransplantation; however, immunosuppression is potentially avoidable between monozygotic twins.

METHODS

A preoperative genetic workup revealed 10/10 human leukocyte antigen homozygosity. Despite substantial phenotypic divergence in size and facial features, the sisters were genotypically identical. A two-stage, double deep inferior epigastric perforator transplant was planned for delayed reconstruction. At the first stage following the resection, an arteriovenous loop was performed to provide recipient vasculature to the back. At a second stage, the transplantation was performed. In addition, bilateral lumbar artery perforator flaps were created to reduce the length of the defect. Intraoperative steroid bolus and a short taper alone were used for immunosuppression.

RESULTS

The resection resulted in a 22 × 29-cm specimen down to the spine. After a 4-day interval for permanent pathologic evaluation, the transplant was successfully transferred between twins. Two arteries and six veins were anastomosed to establish perfusion. Postoperatively, there have been no episodes of rejection or flap compromise at last follow-up (>36 months).

CONCLUSIONS

This case represents one of the few vascularized composite allotransplantations between monozygotic twins, and the only reported successful vascularized composite allotransplantation for a recurrent cancer diagnosis. Oncologic safety depended on 100 percent histocompatibility to avoid immunosuppression. Limited patient donor sites precluded total autologous coverage, and a substantial size discrepancy between the twins favored a transplant.

Fibrosarcomatous dermatofibrosarcoma protuberans from scar following trauma

Dermatofibrosarcoma protuberans (DFSP) is an uncommon soft tissue neoplasm of low metastatic potential notable for its progressive growth and high rate of local recurrence after surgical excision. Fibrosarcomatous transformation of DFSP (FS-DFSP) is a rare variant characterized by higher rates of local recurrence and metastasis. Trauma has been hypothesized as a potential risk factor for the development of DFSP, although clear evidence has been lacking. In this study, we report a case of FS-DFSP that was found arising from a previously stable scar following a traumatic injury. A 49-year-old male was diagnosed with keloid scars following a motor vehicle accident where he sustained trauma. 12 years later, a large tumor developed immediately after a second traumatic event to the primary scar. Pathology of the excisional biopsy specimen demonstrated FS-DFSP with focal areas consistent with keloid and hypertrophic scar. This observation demonstrates the development of DFSP from underlying scar following a clear history of trauma. Furthermore, it suggests trauma as a possible trigger for the fibrosarcomatous transformation of DFSP.